The United Nations is calling on Democratic Republic of Congo President Joseph Kabila to keep his promise to step down amid protests throughout the country over delayed elections.

"The Secretary-General urges all Congolese political actors to remain fully committed to the 31 December 2016 political agreement, which remains the only viable path to the holding of elections, the peaceful transfer of power and the consolidation of stability in the DRC," a statement by U.N. spokesperson Stéphane Dujarric said late Sunday.

That agreement called for Kabila to step down after elections. But the elections, once promised to be held in 2017, have been repeatedly delayed, inciting civil unrest and prompting fears that Kabila may seek to further extend his rule.

Kabila, 46, has ruled the DRC for 17 years and has remained in office, even though his second term officially expired in December 2016.

Sunday's U.N. statement also condemned "violent dispersion of protests by national security forces," particularly in the capital city of Kinshasa, where five protesters were killed in clashes with police on Sunday, according to the U.N.

Police fired shots and tear gas to break up a Catholic mass and arrested altar boys who were among protesters gathering at a Kinshasa church to rally against Kabila.